Sunlight and Nitric Oxide

Our society has grown accustomed to using pills and supplements to replace vital nutrients, like vitamin D. A new study from the European Journal of Applied Physiology hints that not only can vitamins be found in cheaper and better abundance in natural foods, but in increased exposure to sunlight.

For this study, two rays of ultraviolet from about 315 to 400 nanometers on the wavelength spectrum were shined at ten subjects. These subjects then had their nitrate and nitrite levels tested, as well as blood pressure and resting metabolism. This is where things get interesting. An increasingly common drink for endurance athletes is beet juice because of its high nitrate levels. With more nitrate, the body is able to create more nitrite, and in turn create more nitric oxide, which maximizes the efficiency of muscles in physical endurance. Along with athletic improvement, studies have touted that high levels of nitric oxide lower blood pressure and keep blood sugar under control.

Prior studies even claim that exposure to sunlight causes nitrite in the skin to release into the bloodstream and lead to an increase in nitric oxide, as drinking beet juice does. The study’s purpose was to determine just how much ultraviolet light exposure would cause this increase in nitric oxide.

The two rays of light in the experiment were 10 and 20 joules per square centimeter on the skin. The ray of 20 joules was meant to be equivalent to about 30 minutes out in the Mediterranean sun, while the 10 joules ray represented half that time. Of the two rays, only the higher joules made much of a difference. While both rays lowered the resting metabolic rate of subjects, the higher dose was the only one that increased nitrate levels in any significant way.

A common understanding of the science and health community is that weather has a great effect on the physical well-being of an individual. Most often this is simply attributed to a lack of vitamin D in the summer months, but this experiment provides a newer explanation: a lack nitric oxide levels may play a role in the abundance of health ailments that tend to occur in the winter months.

The study’s lead author, Chris Easton, has said that his team is just finishing up data collection to determine if seasonal fluctuation affect the amount of nitric oxide in individuals. When asked about the significance of sunlight exposure to athletes seeking to improve their performance, Easton said there may be some credibility to the claim, but nothing earth-shattering. If so, then the amount of nitric oxide gained from sunlight would pale in comparison to, say, beet juice.

The science is written in stone yet because varying factors such as prior sun exposure and skin tone have not been taken into account. In 2015, Easton and his colleagues conducted an experiment where one group of cyclists received UVA sunlight exposure prior to the race, one applied nitrate gel, and another had both. Control groups had fake exposure and placebo gels. All these groups then embarked on a ten-mile speed trial. Neither UVA exposure nor nitrate gel increased the athletes’ performance by any significant margin on their own, but the group that had both the exposure and the gel did. To some extent, the sunlight exposure did assist the training of these athletes.

It’s unclear whether any serious athlete should focus on exposure to ultraviolet light prior to competition, but we do know that some time in the sun can’t hurt in addition to nitric oxide supplements just as Kyani Nitro and PMD NitroCM.